#ifndef XRPL_APP_LEDGER_LEDGERREPLAYTASK_H_INCLUDED
#define XRPL_APP_LEDGER_LEDGERREPLAYTASK_H_INCLUDED

#include <xrpld/app/ledger/InboundLedger.h>
#include <xrpld/app/ledger/detail/TimeoutCounter.h>
#include <xrpld/app/main/Application.h>

#include <vector>

namespace ripple {
class InboundLedgers;
class Ledger;
class LedgerDeltaAcquire;
class LedgerReplayer;
class SkipListAcquire;
namespace test {
class LedgerReplayClient;
}  // namespace test

class LedgerReplayTask final
    : public TimeoutCounter,
      public std::enable_shared_from_this<LedgerReplayTask>,
      public CountedObject<LedgerReplayTask>
{
public:
    class TaskParameter
    {
    public:
        // set on construct
        InboundLedger::Reason reason_;
        uint256 finishHash_;
        std::uint32_t totalLedgers_;  // including the start and the finish

        // to be updated
        std::uint32_t finishSeq_ = 0;
        std::vector<uint256> skipList_ = {};  // including the finishHash
        uint256 startHash_ = {};
        std::uint32_t startSeq_ = 0;
        bool full_ = false;

        /**
         * constructor
         * @param r  the reason of the task
         * @param finishLedgerHash  hash of the last ledger in the range
         * @param totalNumLedgers  number of ledgers to download
         */
        TaskParameter(
            InboundLedger::Reason r,
            uint256 const& finishLedgerHash,
            std::uint32_t totalNumLedgers);

        /**
         * fill all the fields that was not filled during construction
         * @note called with verified skip list data
         * @param hash  hash of the ledger that has the skip list
         * @param seq  sequence number of the ledger that has the skip list
         * @param sList  skip list
         * @return false if error (e.g. hash mismatch)
         *         true on success
         */
        bool
        update(
            uint256 const& hash,
            std::uint32_t seq,
            std::vector<uint256> const& sList);

        /** check if this task can be merged into an existing task */
        bool
        canMergeInto(TaskParameter const& existingTask) const;
    };

    /**
     * Constructor
     * @param app  Application reference
     * @param inboundLedgers  InboundLedgers reference
     * @param replayer  LedgerReplayer reference
     * @param skipListAcquirer  shared_ptr of SkipListAcquire subtask,
     *        to make sure it will not be destroyed.
     * @param parameter  parameter of the task
     */
    LedgerReplayTask(
        Application& app,
        InboundLedgers& inboundLedgers,
        LedgerReplayer& replayer,
        std::shared_ptr<SkipListAcquire>& skipListAcquirer,
        TaskParameter&& parameter);

    ~LedgerReplayTask();

    /** Start the task */
    void
    init();

    /**
     * add a new LedgerDeltaAcquire subtask
     * @param delta  the new LedgerDeltaAcquire subtask
     * @note the LedgerDeltaAcquire subtasks must be added in order
     */
    void
    addDelta(std::shared_ptr<LedgerDeltaAcquire> const& delta);

    TaskParameter const&
    getTaskParameter() const
    {
        return parameter_;
    }

    /** return if the task is finished */
    bool
    finished() const;

private:
    void
    onTimer(bool progress, ScopedLockType& sl) override;

    std::weak_ptr<TimeoutCounter>
    pmDowncast() override;

    /**
     * Update this task (by a SkipListAcquire subtask) when skip list is ready
     * @param hash  hash of the ledger that has the skip list
     * @param seq  sequence number of the ledger that has the skip list
     * @param sList  skip list
     */
    void
    updateSkipList(
        uint256 const& hash,
        std::uint32_t seq,
        std::vector<uint256> const& sList);

    /**
     * Notify this task (by a LedgerDeltaAcquire subtask) that a delta is ready
     * @param deltaHash  ledger hash of the delta
     */
    void
    deltaReady(uint256 const& deltaHash);

    /**
     * Trigger another round
     * @param sl  lock. this function must be called with the lock
     */
    void
    trigger(ScopedLockType& sl);

    /**
     * Try to build more ledgers
     * @param sl  lock. this function must be called with the lock
     */
    void
    tryAdvance(ScopedLockType& sl);

    InboundLedgers& inboundLedgers_;
    LedgerReplayer& replayer_;
    TaskParameter parameter_;
    uint32_t maxTimeouts_;
    std::shared_ptr<SkipListAcquire> skipListAcquirer_;
    std::shared_ptr<Ledger const> parent_ = {};
    uint32_t deltaToBuild_ = 0;  // should not build until have parent
    std::vector<std::shared_ptr<LedgerDeltaAcquire>> deltas_;

    friend class test::LedgerReplayClient;
};

}  // namespace ripple

#endif
